Crankpin assembly



c. A. WHEELER 2,117,124

CRANKPIN ASSEMBLY Filed July 20, 1957 May 10, 1938.

Patented May 10, 1938 UNiTED STATES PATENT orf-Fien Clarence A. Wheeler, Toronto, Ontario, Canada Application July 20, 1937, Serial No. 154,663

4 Claims.

This invention relates to crank pin assemblies for the driving wheels of locomotives and more particularly to side rod retaining means.

A number of devices have been proposed for 5 preventing the possibility of the side rod from being forced oif the crank pin by sudden violent laterally applied forces, such -devices consisting of a disc-like member secured to the outer end of the crank pin. In the known devices of this kind the disc has been rigidly fastened to the crank pin and has not been entirely satisfactory in operation.

The object of the present invention is to provide an improved side rod retaining device which is free from the objectionable features of the known devices, and with this object in view the retaining member, according to the. present invention, is provided with means for holding it yieldingly in engagement with the outer end of the crank pin.

IIhe invention consists in the combination and arrangement of parts hereinafter describedand more particularly described in the appended claims.

Referring now to the accompanying drawing which illustrates by way of example one convenient embodiment of the invention:

Figure l is a sectional elevation of the improved device and 3o Figure 2 is an end elevation looking on the left hand end of Figure 1.

The crank pin which is shown at I is mounted in the locomotive driving wheel, a part of which is indicated at 2, and the side rod and side rod bushing are indicated in dotted lines at 3 and 4 respectively. The side rod retaining member, preferably of disc-like form, is shown at 5 and is provided with a central perforation 6 which is preferably of a non-circular shape, for example square, as shown in Figure 2. The crank pin I is formed with an axial passage 'l which registers with the perforation 6 and is preferably of the same shape in cross section as the perforation. The passage l opens into a recess 8 at the inside of the wheel, a shoulder 9 being formed surrounding the inner end of the passage 'I.

A tension member I projects through the passage 'I and perforation 6, and is provided at its outer end wtih a slot I I and at its inner end with a head I2. The tension member IIJ is preferably of such cross section that it will not rotate with respect to the crank pin I or the retaining member 5, and may conveniently be made of a substantially square section as shown in Figure 2.

A powerful spring I3 surrounds the member I0 and is compressed between the shoulder 9 and the head I2, the spring being held in compression by suitable means such as a key I 4 projecting through the slot II and engaging the member 5. The spring I3 is so constructed that when at rest the width of each coil is substantially greater than the space between each coil.

In order to avoid a lateral projection of the member Ill beyond the outer face of the member 5 the central part of the member 5 is preferably dished as at I5, to provide a recess to receive the key I4, the crank pin I being formed with a corresponding recess IE into which the central part of the member 5 ts.

It will be seen that the assembling of the device is a simple operation. The member II), with the spring I3 upon it, is inserted through the passage. 'I and aperture B from the inside of the wheel 2. The spring I3 is then compressed by means of any suitable tool (not shown) inserted 20 into the recess B and pressed into engagement with the head I2, causing the slotted end of the member I0 to project beyond the outer face of the member 5. The key I4 is then inserted in the slot II and the tool removed from the recess 8, permitting the spring I3 to expand and cause the projecting ends of the key I4 to be pressed into engagement with the central part of the `member 5. The member 5 in turn is thus pressed firmly into engagement with the outer end of the crank pin I, but lis able to yield to a limited extent when subjected to sufciently powerful forces caused by lateral movement of the side rod 3, and to return the side rod promptly to its normal position. As the width of each coil in the spring I3 is greater than the space between each coil, the spring will still be partially effective to hold, the key I 4 pressed against the. member 5 and the member 5 in engagement with the crank pin I.

After assembly of the device any suitable means such as small projections may be welded in the recess 8, as indicated at I'l, to prevent the inner end of the member IIl from leaving the recess 8 if the member I0 breaks.

It will be understood that the foregoing description and accompanying drawing are given by way of example only and that modifications Within the scope of the appended claims may be resorted to without departing from the invention.

What I claim is:

1. In combination with a driving wheel, a crank pin having an axial aperture, a centrally apertured rod-retaining disc of larger diameter than said crank pin and arranged coaxial therewith, a tension member extending through the apertures in said crank pin and disc, a key extending through a slot adjacent the outer end of said tension member, a head on the inner end of said tension member, and a spring surrounding said tension member and compressed between said head and a shoulder on the crank pin.

2. A crank pin assembly as claimed in claim 1, wherein the central portion of said disc is depressed inwardly, the outer end of the crank pin being recessed to receive said depressed portion, and the outer end of the tension member and the key being disposed within said depressed portion.

3. A crank pin assembly as claimed in claim 1, wherein the inner part of the axial aperture in the crank pin is of larger cross sectional area than the outer portion.

4. A crank pin assembly as claimed in claim 1, wherein the inner part of the axial aperture in the crank pin is of a larger cross sectional area than the outer portion and wherein projecting means are provided at the inner end of the aperture in the crank pin in the path of withdrawal of the tension member.

CLARENCE A. WHEELER. 

